In an arc furnace as a kind of electric arc furnace for melting metal material, a so-called hot spot and cold spot are formed within an inner space of a furnace shell containing the metal material. The hot spot places close to electrodes and at which the metal material is likely to be melted. The cold spot places distant from the electrodes and at which the metal material is not likely to be melted. In the cold spot, there arise a problem that it takes a long period of time to melt the metal material and thus melting of the metal material proceeds uniformly as a whole. In order to solve this problem, Patent Literature 1 proposes a process in which a furnace shell is rotationally displaced around an axis line extending in an up-down direction with respect to electrodes, thereby exchanging between the cold spot and the hot spot. In such the electric arc furnace, thermal nonuniformity within the furnace can be eliminated and an amount of wasteful power consumption can be reduced by rotationally displacing the furnace shell, without consuming power for a pump at an extra water-cooled part like in a shaft furnace and without additionally supplying burner combustion energy or the like for a composition appropriating processing of exhaust gas.
Patent Literature 1: JP-A-2014-40965